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Myocardin expression during avian embryonic heart development requires the endoderm but is independent of BMP signaling
Author(s) -
Warkman Andrew S.,
Yatskievych Tatiana A.,
Hardy Katharine M.,
Krieg Paul A.,
Antin Parker B.
Publication year - 2008
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/dvdy.21393
Subject(s) - myocardin , endoderm , mesoderm , biology , fgf and mesoderm formation , microbiology and biotechnology , serum response factor , heart development , intermediate mesoderm , bone morphogenetic protein , embryogenesis , transcription factor , embryonic stem cell , ectoderm , embryo , genetics , gene
Myocardin , a serum response factor cofactor, plays an important role in regulating heart and smooth muscle development. To investigate myocardin function during early stages of heart development, we isolated the chicken orthologue of myocardin and characterized its expression between Hamburger and Hamilton stages 3 and 15. At stage 4, myocardin transcripts are detected in the lateral and extraembryonic mesoderm, become progressively localized to the precardiac mesoderm and the differentiated myocardium and are also seen in smooth muscle cells of the developing vascular plexus. Surprisingly, myocardin expression within the developing chicken embryo precedes that of the homeodomain transcription factor Nkx2.5 . Embryonic dissection studies demonstrate that signals from the endoderm are required for myocardin expression within the precardiac mesoderm. However, unlike Nkx2.5 , myocardin expression is not regulated by bone morphogenetic protein (BMP) signaling. These results suggest that initial expression of myocardin in the precardiac mesoderm is regulated by a signaling pathway that is parallel to, and independent of, Nkx2.5 expression. Developmental Dynamics 237:216–221, 2008. © 2007 Wiley‐Liss, Inc.